1. Field of the Invention
This invention relates to continuous form stationery comprising stuffed sealed envelope assemblies of the type which are manually or automatically processed on computers or other business machines by the typing or printing of information on selected plies thereof. More particularly, it relates to the improvement over the invention disclosed in U.S. Pat. Nos. 3,777,971 and 3,830,141 issued to Donald J. Steidinger on Dec. 11, 1973 and Aug. 20, 1974, respectively.
While the present invention is described herein with reference to particular embodiments, it should be understood that the invention is not limited thereto. The envelope assembly of the present invention may be employed in a variety of forms, as those skilled in the art will recognize in the light of the present disclosure.
2. Description of the Prior Art
Presealed envelope assemblies of the type contemplated herein are well known in the prior art and are presently receiving extensive commercial acceptance. Representative of the prior art are such U.S. Pat. Nos. as Wanser 2,148,886, Sherman 2,257,766, Steidinger 3,104,799, Hanrahan 3,186,735, Steidinger 3,339,827, Steidinger 3,437,259, Bell 3,552,641, Van Malderghem 3,554,438, the aforementioned Steidinger 3,777,971 and 3,830,141, and DiGirolomo 3,941,308 and the various patents cited therein.
A requirement common to such types of stuffed sealed envelopes is the need for maintaining registration of the insert ply relative to the external plies so that indicia typed, printed or otherwise applied to the external ply for reproduction on an internal ply will be properly located within predetermined tolerances. This problem is aggravated by the high speed processing of the forms on modern business machines, such as automatic typewriters, billing and addressing machines, high speed printers associated with computers, and the like. Unless the insert plies are substantially immobilized relative to the external plies, the bending, flexing and substantial acceleration and deceleration to which the assemblies are subjected can cause excessive displacement of the insert plies to the point where subsequently added indicia are misplaced on the insert ply or plies, causing misalignment, misregistration and/or overprinting with consequent confusion, misreading, and aesthetically unacceptable results.
One prior art technique for immobilizing the insert ply is to attach or otherwise secure at least one margin of the insert plies to one or both of the external plies. For certain purposes, this approach is considered disadvantageous or otherwise undesired. For example, for certain uses it requires that the addressee trim or detach the insert plies from the external plies -- an extra and inconvenient step and one which can result in tearing of the insert material.
The use of free insert plies, that is, plies which are not attached to the external plies in any way, avoids this problem and is a feature of the aforementioned Steidinger U.S. Pat. Nos. 3,777,971 and 3,830,141. The insert plies are maintained in substantial registration by means of embossments in the form of upraised portions or projections relative to the envelope back which are positioned within the perimeter defined by the perimetric lines of glue. Movement of the insert is effectively limited within specifications by abutment of the insert against the embossments.
In practice, however, unanticipated problems have arisen. If the embossments are not properly formed at the outset, consistent abutment may not occur and an insert ply or plies may wedge past the embossment into a misregistered position. Even if properly formed at the outset, mishandling of the forms or subjecting them to excessive pressures may cause flattening or other deformation of the embossments, resulting in the same problem.
Moreover, multiple and excessively-thick insert plies necessitate the presence of unduly large embossments or bumpers and may require special handling or complicate the manufacturing procedures. Furthermore, under certain circumstances the entire front ply may be removed from the sealed envelope during an automatic opening operation. The upraised embossments are thereby rendered ineffectual for holding or maintaining the insert ply in registration on the back ply.